5F2A high Squeal new build

[Bangy]

I have built 3 of these. First two I am using Doug's PT and OT, Heyboer in his parts list.

Dougs illustration shows the OT Primary leads to have the Blue primary OT ead to pin 3 of V2 and the Red primary OT  lead to pin 8 of V3.

Build 1 I swapped these by mistake blue to V3P8, Red to V2P3-- The amp works fine.

Build 2 - I corrected my 'mistake' and followed Dougs diagram. For weeks I have pulled out my hair, but thinking the feedback (high sequel builds in intensity) and I suspected the maybe ground loops but then i removed the 22K negative feed back resistor, and Bingo the amp works fine.

So by removing the feedback circuit, I solved the feedback issue.

Questions:
1). Is Dougs diagram wrong and I am actually introducing positive feedback to the circuit? Should I reverse the OT leads to blue to V3 and red to V2

The 22k resistor is good. . .

I am feeling confident as all get out, the NFB is the issue.

Help PLEASE, smart people. . . What should I do next???? Swap primary OT leads in what my pea brain thinks. . . .

Bangy.

[sluckey]

Now that you have proved that the NFB phase is wrong by disconnecting the NFB resistor you should reverse the OT primary leads to correct the problem. And put the resistor back on the board.

You should know by now "don't believe the color of the primary wires". Leave the length of the wires long until you absolutely know the NFB phase is correct. There's a 50/50 chance you will need to reverse them.

[Bangy]

Excellent Sluckey--Mission accomplished.  Thanks for the help.  Im off to fix the problems now!

[Bangy]

I unsoldered the OT primary leads to V2 and V3 then with jumpers I reversed the polairity AND I used a variable resister box set (and calibrated) to 22K for the NFB and tone was superb, however very quiet, but weak gain, and not very loud, even dimed  i dint break up. BUT NO Positive feedback squeal.

Can lead dress (essentially my jumpers and resister box) cause this symptom?  I plan to solder up the fixes (swapped primary OT leads) and then see what the new normal is.  Just seeing what you think? Im don for tonight.

So new guys reading this-UNDERSTND the OT primary phase is important and the protocol is to leave your leads long until you find out which Lead goes to V2 and which V3, apparently the colors are not normalized one way or another.  Magnetic corp or Classictone manufacturers will give you this info via email, not sure about Heyboer. I went by Dougs diagram color scheme and for some OT's it may be correct but for the Heyboer--it is not correct.

Hope this helps someone, Ive sure got a ton from this forum. . . .BAngy